Re: Official Linux system wrapper library?
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From: Michael Kerrisk (man-pages) <hidden>
Date: 2018-11-11 06:55:38
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[adding in glibc folk for comment] On 11/10/18 7:52 PM, Daniel Colascione wrote:
Now that glibc is basically not adding any new system call wrappers, how about publishing an "official" system call glue library as part of the kernel distribution, along with the uapi headers? I don't think it's reasonable to expect people to keep using syscall(__NR_XXX) for all new functionality, especially as the system grows increasingly sophisticated capabilities (like the new mount API, and hopefully the new process API) outside the strictures of the POSIX process.
As a quick glance at the glibc NEWS file shows, the above is not quite true: [[ Version 2.28 * The renameat2 function has been added... * The statx function has been added... Version 2.27 * Support for memory protection keys was added. The <sys/mman.h> header now declares the functions pkey_alloc, pkey_free, pkey_mprotect... * The copy_file_range function was added. Version 2.26 * New wrappers for the Linux-specific system calls preadv2 and pwritev2. Version 2.25 * The getrandom [function] have been added. ]] I make that 11 system call wrappers added in the last 2 years. That said, of course, there are many system calls that lack wrappers [1], and the use of syscall() is undesirable. The glibc folk do have their reasons for being conservative around adding system calls (https://lwn.net/Articles/655028/). However, at this point, I think one of the limiting factors is developer time on the glibc project. Quite possibly, they just need some help to add more (properly designed) wrappers faster. Cheers, Michael [1] https://sourceware.org/bugzilla/show_bug.cgi?id=6399 is a longstanding example. -- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ Linux/UNIX System Programming Training: http://man7.org/training/